1. Field of the Invention
The present invention relates generally to exhaust fans and, more particularly, to exhaust fans for removing airborne materials.
2. Related Art
Stationary and portable fans have been known for years and have been used for numerous applications. One use of exhaust fans of particular pertinence to the present invention is the removal of airborne contaminants from a localized area. As used herein, the term airborne material refers to any particles, fumes, dust, chemicals or other materials that are suspended in the air.
There are many drawbacks to traditional exhaust fans used for removing various airborne materials in different applications. In particular, there are significant drawbacks associated with conventional exhaust fans that are used for removing from a localized area overspray from spray painting, airborne dust from surface sanding, airborne chemicals from painting, varnishing, staining and similar activities.
One such drawback is that conventional exhaust fans expose the air traveling through the fan to events that can ignite flammable airborne materials. Thus, conventional exhaust fans are generally inappropriate to be used to remove safely from a localized area air having flammable or combustible airborne materials.
Another drawback is that currently available exhaust fans do not protect the internal components of the fan from the air passing therethrough, resulting in an accumulation of materials on such internal components. Certain airborne materials such as paint overspray readily accumulate on the internal components of the fan such as the fan blade, blade shaft, grating, electrical components, etc. This requires conventional fans to be periodically disassembled and cleaned. Unfortunately, such conventional fans cannot be disassembled. As result Oftentimes, an exhaust fan used in such applications must be discarded once a significant amount of material accumulates on the fan components, adversely affecting the operating performance of the fan.
Another significant drawback to conventional exhaust fans is that they often do not clean the air before releasing it into the surrounding environment. That is, the airborne materials are not removed from the air. As a result, such conventional exhaust fans are unsuitable for use in may communities in which clear air standards have been established.
What is needed, therefore, is am exhaust fan that can safely remove airborne contaminants from a localized area without damaging the exhaust fan itself or releasing the materials into the surrounding environment.